1. Field of the Invention
The present invention relates to a copying machine and more specifically to a copying machine having a prohibiting unit which prohibits the operation of an automatic document take-up unit in case a document turnover unit is not attached. 2. DISCUSSION OF THE BACKGROUND
The conventional copying machine is composed of a copying machine body 30 as shown in FIG. 1 and a control unit (not shown.)
The copying machine body 30 has a glass plate 315 on which a document 90 to be copied is placed and scanned optically, and a copy image forming unit 33 which scans optically the document 90 placed on the glass plate 315, forms an electrostatic latent image on a photosensitive medium, further, transfers the electrostatic latent image on a sheet of copy paper 95 after development and then, letters, figures and etc., appear on the copy paper 95.
The following units can be attached to the copying machine body 30;
an automatic document take-up unit 35 which holds and feeds documents 90, a document feeder 31 which feeds said documents 90 to a fixed place on the glass plate 315, and a document turnover unit 41 which turns over both sides of the document 90 and carries it to the glass plate 315, so that the opposite side 92 of the document 90 can contact the glass plate 315. This document turnover unit 41 can be attached to a turnover unit holder 37. The automatic document take-up unit 35, combining with the document feeder 31, is called an automatic document feeder (hereinafter referred to as A.D.F.) generically.
Also, this copying machine with an A.D.F. has a function to copy both sides of the document 90 on both sides of a sheet of copy paper 95 and to copy both sides of the document 90 on one side of two sheets of copy paper 95.
It is necessary to attach the document turnover unit 41 to the turnover unit holder 37 in order to copy the opposite side 92 of the document 90 on a sheet of copy paper automatically. Normally, the document turnover unit 41, the document feeder 31 and the automatic document take-up unit 35 will be sold on the market separately from the copying machine body 30. Some copy machine users do not have the document turnover unit 41. Further, there may be some users who do not know that the opposite side 92 of the document 90 can not be copied even if the document was set on the automatic document take-up unit 35 and the prescribed operation was carried out according to an instruction from an operation panel when the document turnover unit 41 was not attached to the copying machine body 30.
Therefore, an object of the present invention is to provide the copying machine with a function to prohibit the automatic document take-up unit 35 from working even if a prescribed operation is carried out according to an instruction from the operation panel when the document turnover unit 41 is not attached to the copying machine body 30.